The Effect of Titania Additives on the Performance of PEO-Based Solid Sodium Batteries: Bulk and Interfacial Aspects

Nanometric fillers are known to affect the electrochemical performance of polymer electrolytes. Here, nanowires and nanotubes of TiO2 with the same crystal structure are compared as additives to poly(ethylene oxide) based electrolytes for solid state sodium batteries. Electrochemical studies of symmetric cells with blocking and non-blocking electrodes examined the effects of the additive shapes on the bulk electrolyte and Na-electrolyte interface. Impedance spectroscopy was used as a major electroanalytical tool. To obtain a full perspective, all-solid-state batteries were evaluated. In galvanostatic measurements the filler shape effect is most noticeable at a high current density. TiO2 nanotubes improve the solid electrolyte behavior considerably more than titania nanowires. This effect is related mainly to the interface of the polymeric matrix with the electrodes.